Vitamin K-dependent coagulation system (VKDCS)

The Vitamin K-dependent coagulation system is a complex physiological pathway essential for the activation of several key proteins involved in blood clotting and hemostasis [1, 3]. This system relies on the Vitamin K cycle, where the enzyme Vitamin K epoxide reductase (VKORC1) recycles Vitamin K to its active hydroquinone form, which then acts as a cofactor for gamma-glutamyl carboxylase (GGCX) [5, 10]. GGCX facilitates the post-translational gamma-carboxylation of glutamic acid residues on procoagulant factors (II, VII, IX, and X) and anticoagulant proteins (C, S, and Z), a modification necessary for their calcium-binding and membrane-associating properties [6, 14]. Beyond coagulation, Vitamin K-dependent proteins like osteocalcin and matrix Gla protein play roles in bone metabolism and the prevention of vascular calcification [15, 20]. Clinical disorders associated with this system include Vitamin K deficiency bleeding and various thrombotic conditions resulting from genetic mutations or acquired deficiencies [9, 13]. Pharmacologically, the system is the primary target for Vitamin K antagonists such as warfarin, which inhibit VKORC1 to reduce the functional levels of clotting factors for anticoagulation therapy [7, 11]. However, these drugs require careful monitoring due to a narrow therapeutic index, significant bleeding risks, and susceptibility to dietary and genetic variations [12, 19].

Other names

Vitamin K-dependent clotting factorsVitamin K cycleVitamin K-dependent proteinsVKDPsVitamin K-dependent hemostatic system

Inhibition of Vitamin K epoxide reductase (VKORC1) to prevent the recycling of Vitamin K, leading to the production of under-carboxylated and functionally inactive coagulation factors II, VII, IX, and X [7, 11, 13].